The present subject matter relates to an artificial valve and related methods for implantation in a patient's blood vessel, in particular an artificial heart valve, and further relates to a valve system including such an artificial valve.
Artificial heart valves are generally designed to replace the natural heart valve and to perform its function over many years, preferably until the person (or animal) dies. Thus, besides the general requirement that artificial valves must be made from a material that is compatible with the patient's blood and tissue, the valve must furthermore be extremely reliable.
Typical artificial heart valves are strictly mechanical, such as mechanical mono- or bi-leaflet valves and ball valves. A leaflet valve may for instance comprise a tilting disc hinged to an annular ring that is sutured into the blood vessel. The blood pressure changes of typically between 80 mmHg and 120 mmHg cause the disc to swing between an open and a closed position. In ball valves, a ball is held in a cage and allowed to move therein upon blood pressure changes between a closed position in which it seals an annular ring sutured into the blood vessel and an open position in which the ball is at a distance from the ring, thereby permitting blood to flow around the ball.
While there are many different types of artificial valves for implantation in a patient's blood vessel, they all suffer from the draw back of material fatigue resulting in breakage of parts thereof. Disfunctioning of the valve is only one severe consequence thereof. The consequences may be fatal when broken parts are carried away with the blood stream and block the blood stream at remote locations. Another problem arising with artificial valves implanted in blood vessels is the danger of generating thromboses as well as fibrosis forming and growing on the valve elements. Particularly the latter may prevent complete closing of the valve, thereby causing valve insufficiency.